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BUG: KASAN: slab-out-of-bounds in firmware_param_path_get+0x348/0x350 drivers/base/firmware_loader/main.c:531
Write of size 1 at addr ffff88813db93fff by task syz.1.316/1687

CPU: 1 PID: 1687 Comm: syz.1.316 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x10f/0x150 mm/kasan/report.c:444
 __asan_report_store1_noabort+0x17/0x20 mm/kasan/report_generic.c:311
 firmware_param_path_get+0x348/0x350 drivers/base/firmware_loader/main.c:531
 param_attr_show+0x150/0x1b0 kernel/params.c:567
 module_attr_show+0x56/0x70 kernel/params.c:886
 sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61
 kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168
 seq_read_iter+0x472/0xce0 fs/seq_file.c:230
 kernfs_fop_read_iter+0x146/0x460 fs/kernfs/file.c:241
 call_read_iter include/linux/fs.h:2212 [inline]
 generic_file_splice_read+0x3ea/0x5f0 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x40f/0xb40 fs/splice.c:870
 do_splice_direct+0x1c2/0x2d0 fs/splice.c:979
 do_sendfile+0x515/0xe20 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0x199/0x1f0 fs/read_write.c:1303
 x64_sys_call+0x88d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff0333fc1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff029a13028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ff033684180 RCX: 00007ff0333fc1d9
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000009
RBP: 00007ff033493888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff033684218 R14: 00007ff033684180 R15: 00007ffe520d1d08
 </TASK>

Allocated by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88813db92000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 4095 bytes to the right of
 4096-byte region [ffff88813db92000, ffff88813db93000)
The buggy address belongs to the page:
page:ffffea0004f6e400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13db90
head:ffffea0004f6e400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 0000000000000000 dead000000000122 ffff888100043380
raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 1687, ts 77186014666, free_ts 77165032047
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1937 [inline]
 new_slab+0xa0/0x4d0 mm/slub.c:2000
 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033
 __slab_alloc+0x49/0x90 mm/slub.c:3120
 slab_alloc_node mm/slub.c:3211 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc+0x16a/0x2c0 mm/slub.c:4432
 __kmalloc_node include/linux/slab.h:487 [inline]
 kmalloc_node include/linux/slab.h:642 [inline]
 kvmalloc_node+0x211/0x320 mm/util.c:621
 kvmalloc include/linux/mm.h:862 [inline]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x1f1/0xce0 fs/seq_file.c:210
 kernfs_fop_read_iter+0x146/0x460 fs/kernfs/file.c:241
 call_read_iter include/linux/fs.h:2212 [inline]
 generic_file_splice_read+0x3ea/0x5f0 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x40f/0xb40 fs/splice.c:870
 do_splice_direct+0x1c2/0x2d0 fs/splice.c:979
 do_sendfile+0x515/0xe20 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0x199/0x1f0 fs/read_write.c:1303
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1474 [inline]
 free_pcp_prepare mm/page_alloc.c:1546 [inline]
 free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536
 free_unref_page+0xae/0x540 mm/page_alloc.c:3618
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5900
 __free_slab+0xe5/0x1e0 mm/slub.c:2025
 free_slab mm/slub.c:2040 [inline]
 discard_slab mm/slub.c:2046 [inline]
 __unfreeze_partials+0x15a/0x190 mm/slub.c:2532
 put_cpu_partial+0xc6/0x120 mm/slub.c:2612
 __slab_free+0x1d4/0x290 mm/slub.c:3395
 do_slab_free mm/slub.c:3514 [inline]
 ___cache_free+0x104/0x120 mm/slub.c:3535
 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:443
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3245 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc+0x120/0x2c0 mm/slub.c:4432
 __kmalloc_node include/linux/slab.h:487 [inline]
 kmalloc_node include/linux/slab.h:642 [inline]
 kvmalloc_node+0x211/0x320 mm/util.c:621
 kvmalloc include/linux/mm.h:862 [inline]
 simple_xattr_alloc+0x43/0xa0 fs/xattr.c:987

Memory state around the buggy address:
 ffff88813db93e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88813db93f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88813db93f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff88813db94000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88813db94080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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